Fix bad assumptions about Cypher MERGE with media saving

How it actually works is if the complete pattern doesn't exist,
then the complete pattern is created.
Which means if the media didn't exist, it would create a FileVersion node.
We never want to create a FileVersion node here,
so pull that out to a match
and only merge if we have a FileVersion given.

Author: CarsonF

src/components/file/media/detect-existing-media.migration.ts

@@ -6,7 +6,7 @@ import { FileVersion } from '../dto';
 import { FileRepository } from '../file.repository';
 import { MediaService } from './media.service';
 
-@Migration('2023-09-06T12:00:00')
+@Migration('2023-09-06T13:00:00')
 export class DetectExistingMediaMigration extends BaseMigration {
   constructor(
     private readonly mediaService: MediaService,
@@ -18,6 +18,7 @@ export class DetectExistingMediaMigration extends BaseMigration {
   async up() {
     await this.fixVideoLabels();
     await this.fixVideoBuggedDuration();
+    await this.fixFileVersionFromBuggedMediaMerge();
     await this.dropAllDuplicatedMedia();
 
     const detect = async (f: FileVersion) => {
@@ -99,6 +100,18 @@ export class DetectExistingMediaMigration extends BaseMigration {
     `.executeAndLogStats();
   }
 
+  private async fixFileVersionFromBuggedMediaMerge() {
+    await this.db.query().raw`
+      match (badFv:FileVersion)
+      where not badFv:BaseNode
+      with badFv
+      match (realFv:FileVersion:BaseNode { id: badFv.id }),
+        (badFv)-->(media:Media)
+      merge (realFv)-[:media]->(media)
+      detach delete badFv
+    `.executeAndLogStats();
+  }
+
   private async dropAllDuplicatedMedia() {
     await this.db.query().raw`
       match (fv:FileVersion)-->(media:Media)

src/components/file/media/media.repository.ts

@@ -49,17 +49,27 @@ export class MediaRepository extends CommonRepository {
     const res = input.__typename
       ? EnhancedResource.of(resolveMedia(input as AnyMedia))
       : undefined;
+    const tempId = await generateId();
     const query = this.db
       .query()
-      .merge([
-        node('fv', 'FileVersion', input.file ? { id: input.file } : {}),
-        relation('out', '', 'media'),
-        node('node', 'Media', input.id ? { id: input.id } : {}),
+      .match([
+        input.file ? [node('fv', 'FileVersion', { id: input.file })] : [],
+        input.id ? [node('node', 'Media', { id: input.id })] : [],
       ])
-      .onCreate.set({
-        values: { 'node.id': await generateId() },
-        variables: { 'node.createdAt': 'datetime()' },
-      })
+      .apply((q) =>
+        input.file
+          ? q
+              .merge([
+                node('fv'),
+                relation('out', '', 'media'),
+                node('node', input.id ? undefined : 'Media'),
+              ])
+              .onCreate.set({
+                values: { 'node.id': tempId },
+                variables: { 'node.createdAt': 'datetime()' },
+              })
+          : q,
+      )
       .setValues({ node: toDbShape(input) }, true)
       .with('node, fv')
       // Update the labels if typename is given, and maybe changed.